Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933288AbcL0QKZ (ORCPT ); Tue, 27 Dec 2016 11:10:25 -0500 Received: from mail-pg0-f68.google.com ([74.125.83.68]:34638 "EHLO mail-pg0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933116AbcL0QJp (ORCPT ); Tue, 27 Dec 2016 11:09:45 -0500 From: Ming Lei To: Jens Axboe , linux-kernel@vger.kernel.org Cc: linux-block@vger.kernel.org, Christoph Hellwig , Ming Lei , Mike Christie , Hannes Reinecke , Kent Overstreet , Chaitanya Kulkarni , Shaun Tancheff , Johannes Thumshirn , Bart Van Assche Subject: [PATCH v1 30/54] block: bio: introduce single/multi page version of bio_for_each_segment_all() Date: Tue, 27 Dec 2016 23:56:19 +0800 Message-Id: <1482854250-13481-31-git-send-email-tom.leiming@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1482854250-13481-1-git-send-email-tom.leiming@gmail.com> References: <1482854250-13481-1-git-send-email-tom.leiming@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2560 Lines: 69 This patches introduce bio_for_each_segment_all_sp() and bio_for_each_segment_all_mp(). bio_for_each_segment_all_sp() is for replacing bio_for_each_segment_all() in case that the returned bvec has to be single page bvec. bio_for_each_segment_all_mp() is for replacing bio_for_each_segment_all() in case that user wants to update the returned bvec via the pointer. Signed-off-by: Ming Lei --- include/linux/bio.h | 24 ++++++++++++++++++++++++ include/linux/blk_types.h | 6 ++++++ 2 files changed, 30 insertions(+) diff --git a/include/linux/bio.h b/include/linux/bio.h index 79079bc5a1be..efa0b3627735 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -217,6 +217,30 @@ static inline void bio_advance_iter_mp(struct bio *bio, struct bvec_iter *iter, #define bio_for_each_segment_mp(bvl, bio, iter) \ __bio_for_each_segment_mp(bvl, bio, iter, (bio)->bi_iter) +/* + * This helper returns each bvec stored in bvec table directly, + * so the returned bvec points to one multipage bvec in the table + * and caller can update the bvec via the returnd pointer. + */ +#define bio_for_each_segment_all_mp(bvl, bio, i) \ + bio_for_each_segment_all((bvl), (bio), (i)) + +/* + * This helper returns singlepage bvec to caller, and the sp bvec + * is generated in-flight from multipage bvec stored in bvec table. + * So we can _not_ change the bvec stored in bio->bi_io_vec[] via + * this helper. + * + * If someone need to update bvec in the table, please use + * bio_for_each_segment_all_mp() and make sure it is correctly used + * since the bvec points to one multipage bvec. + */ +#define bio_for_each_segment_all_sp(bvl, bio, i, bi) \ + for ((bi).iter = BVEC_ITER_ALL_INIT, i = 0, bvl = &(bi).bv; \ + (bi).iter.bi_idx < (bio)->bi_vcnt && \ + (((bi).bv = bio_iter_iovec((bio), (bi).iter)), 1); \ + bio_advance_iter((bio), &(bi).iter, (bi).bv.bv_len), i++) + #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len) static inline unsigned __bio_segments(struct bio *bio, bool mp) diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index 519ea2c9df61..ef8e30abb099 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -89,6 +89,12 @@ struct bio { #define BIO_RESET_BYTES offsetof(struct bio, bi_max_vecs) +/* this iter is only for implementing bio_for_each_segment_rd() */ +struct bvec_iter_all { + struct bvec_iter iter; + struct bio_vec bv; /* in-flight singlepage bvec */ +}; + /* * bio flags */ -- 2.7.4